If chords are ll then alternate interior angels equal each other
ABC equal BCD.
angle BAC =90 degree
angle BDC =90 degree because both lie on diameter.
triangle BAC congruent to BDC because the same side BC and two angles.
so AC=BD from congruence of triangles

AO=BO=CO definition of circumcircle which is enter of the circle that passes through all three vertices of the triangle.
triangle ABO congruent to triangle AOC
because of side and two angles ASA
angle ABO=BAO=CAO=OCA
so AB=AC from congruence of triangles

Let x to be the speed of the plane in still air.
x+30 will be speed with wind
x-30 - speed against the wind.
since the time will be the same in both directions we can make the equation.
the basic formula for rate and time is t=distance/speed
200/x-30 = 300/x+30
solve...

Let time = x
identify velocity for both ants.
first ant has the velocity 139.61/23 =6.07 cm/min
the second ant has velocity 88/1.6 =55cm/min
they both traveled the same time
the equation will look: 6.07x +55x =150.41
solve for x